How tillite weathering during the snowball Earth aftermath induced cap carbonate deposition

Geology ◽  
2012 ◽  
Vol 40 (11) ◽  
pp. 1027-1030 ◽  
Author(s):  
Sébastien Fabre ◽  
Gilles Berger
Keyword(s):  
Snowball Earth ◽  
Cap Carbonate ◽  
Carbonate Deposition

scholarly journals Episode of intense chemical weathering during the termination of the 635 Ma Marinoan glaciation

2016 ◽  
Vol 113 (52) ◽  
pp. 14904-14909 ◽  
Author(s):  
Kang-Jun Huang ◽  
Fang-Zhen Teng ◽  
Bing Shen ◽  
Shuhai Xiao ◽  
Xianguo Lang ◽  
...  
Keyword(s):  
South China ◽  
Chemical Weathering ◽  
Snowball Earth ◽  
Carbonate Precipitation ◽  
Isotopic Data ◽  
Low Intensity ◽  
Cap Carbonates ◽  
Cap Carbonate ◽  
Carbonate Deposition ◽  
Global Precipitation

Cryogenian (∼720–635 Ma) global glaciations (the snowball Earth) represent the most extreme ice ages in Earth’s history. The termination of these snowball Earth glaciations is marked by the global precipitation of cap carbonates, which are interpreted to have been driven by intense chemical weathering on continents. However, direct geochemical evidence for the intense chemical weathering in the aftermath of snowball glaciations is lacking. Here, we report Mg isotopic data from the terminal Cryogenian or Marinoan-age Nantuo Formation and the overlying cap carbonate of the basal Doushantuo Formation in South China. A positive excursion of extremely high δ26Mg values (+0.56 to +0.95)—indicative of an episode of intense chemical weathering—occurs in the top Nantuo Formation, whereas the siliciclastic component of the overlying Doushantuo cap carbonate has significantly lower δ26Mg values (<+0.40), suggesting moderate to low intensity of chemical weathering during cap carbonate deposition. These observations suggest that cap carbonate deposition postdates the climax of chemical weathering, probably because of the suppression of carbonate precipitation in an acidified ocean when atmospheric CO2 concentration was high. Cap carbonate deposition did not occur until chemical weathering had consumed substantial amounts of atmospheric CO2 and accumulated high levels of oceanic alkalinity. Our finding confirms intense chemical weathering at the onset of deglaciation but indicates that the maximum weathering predated cap carbonate deposition.

Geochronological constraints on Neoproterozoic rifting and onset of the Marinoan glaciation from the Kingston Peak Formation in Death Valley, California (USA)

Geology ◽  
2020 ◽  
Vol 48 (11) ◽  
pp. 1083-1087 ◽  
Author(s):  
Lyle L. Nelson ◽  
Emily F. Smith ◽  
Eben B. Hodgin ◽  
James L. Crowley ◽  
Mark D. Schmitz ◽  
...  
Keyword(s):  
Thermal Ionization Mass Spectrometry ◽  
Death Valley ◽  
Snowball Earth ◽  
Ionization Mass ◽  
Glacial Deposit ◽  
Cap Carbonate ◽  
Depositional Age ◽  
Geochronological Constraints ◽  
Kingston Peak Formation ◽  
Discontinuous Fault

Abstract Death Valley (California, USA) hosts iconic Cryogenian snowball Earth deposits, but the lack of direct geochronological constraints has permitted a variety of correlations and age models. Here, we report two precise zircon U-Pb isotope dilution–thermal ionization mass spectrometry dates for the Kingston Peak Formation: a volcanic eruptive age of 705.44 ± 0.28 Ma from the synglacial Limekiln Spring Member, and a maximum depositional age of 651.69 ± 0.64 Ma from the nonglacial Thorndike submember, which is below the Wildrose diamictite. These dates confirm that the Limekiln Spring and Surprise Members were deposited during the Sturtian glaciation, while the Wildrose submember is a Marinoan glacial deposit, and the overlying Sentinel Peak Member of the Noonday Formation is a Marinoan cap carbonate. Additionally, the age from the Thorndike submember supersedes existing radioisotopic ages from the Datangpo Formation in South China as the youngest constraint on the onset of the Marinoan glaciation, demonstrating that the Cryogenian nonglacial interlude lasted for at least 9 m.y. and the Marinoan glaciation was &lt;17 m.y. long. Cryogenian glaciation in western Laurentia occurred against the backdrop of ∼85 m.y. of episodic rift-related subsidence and magmatism within laterally discontinuous, fault-bound basins.

Trace and rare earth elemental investigation of a Sturtian cap carbonate, Pocatello, Idaho: Evidence for ocean redox conditions before and during carbonate deposition

2012 ◽  
Vol 192-195 ◽  
pp. 89-106 ◽  
Author(s):  
Edward E. Meyer ◽  
Andrew N. Quicksall ◽  
Joshua D. Landis ◽  
Paul K. Link ◽  
Benjamin C. Bostick
Keyword(s):  
Rare Earth ◽  
Redox Conditions ◽  
Cap Carbonate ◽  
Carbonate Deposition

scholarly journals Microbial activity records in Marinoan Snowball Earth postglacial transition layers connecting diamictite with cap carbonate (Otavi Group, NW-Namibia)

2017 ◽  
Vol 110 (1) ◽  
Author(s):  
Ildikó Gyollai ◽  
Márta Polgáry ◽  
Krisztián Fintor ◽  
Elemér Pál-Molnár ◽  
Friedrich Popp ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Snowball Earth ◽  
Transition Layers ◽  
Cap Carbonate

Soft-sediment deformation at the base of the Neoproterozoic Puga cap carbonate (southwestern Amazon craton, Brazil): Confirmation of rapid icehouse to greenhouse transition in snowball Earth

Geology ◽  
2003 ◽  
Vol 31 (7) ◽  
pp. 613 ◽  
Author(s):  
Afonso César Rodrigues Nogueira ◽  
Claudio Riccomini ◽  
Alcides Nóbrega Sial ◽  
Candido Augusto Veloso Moura ◽  
Thomas Rich Fairchild
Keyword(s):  
Snowball Earth ◽  
Soft Sediment ◽  
Cap Carbonate ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

Origin of giant wave ripples in snowball Earth cap carbonate

Geology ◽  
2012 ◽  
Vol 40 (9) ◽  
pp. 827-830 ◽  
Author(s):  
Michael P. Lamb ◽  
Woodward W. Fischer ◽  
Timothy D. Raub ◽  
J. Taylor Perron ◽  
Paul M. Myrow
Keyword(s):  
Snowball Earth ◽  
Cap Carbonate

The new occurrence of Marinoan cap carbonate in Brazil: The expansion of snowball Earth events to the southwesternmost Amazon Craton

2017 ◽  
Vol 76 ◽  
pp. 446-459 ◽  
Author(s):  
Valber do Carmo de Souza Gaia ◽  
Afonso César Rodrigues Nogueira ◽  
Fábio Henrique Garcia Domingos ◽  
Pierre Sans-Jofre ◽  
José Cavalcante da Silva Bandeira ◽  
...  
Keyword(s):  
Snowball Earth ◽  
Cap Carbonate
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